Searchlight



June 3, 1930. F. R. HOUSE 6 1,761,668

S EARCHLIGH'I Filed March 19, 1924 2 Sheets-Sheet l Ill I I ,.-mn

45 6 4/ 62 Q 516 6:; 1! an 57 22 5 l il 68 1 92 l mm EDWIN Summon f/JANK$900.65

June 3, 1930. F. R. HOUSE 1,761,668

SEARCHLIGHT Filed March 19, 1924 2 Sheets-Sheet 2 A I IV ..lullll: i

II [I II llli [Illllll llllllll llllll Patented June. 3, 1930 Um'rnbSTATES FRANK R HOUSE, OF BALDWIN HARBOR, LONG- ISLAND, NEW YORK,ASSIGNOR, BY MESNE ASSIGNMENTS, T9 SPERBY GYROSCOPE COMPANY, INC., AGORFORATIQN 01! NEW YORK SEARCHLTGHT Application filed March it, 19%.aerial No. M0385.

This invention relates to high intensity searchlights but moreparticularly to the feeding mechanism for the electrodes. The inventionhas for its principal object the provision of a greatly simplified butmore efiicient means for feeding both the positive and the negativeelectrodes in such manner as to insure the maintenance of a constant arclength. y

W This invention has for one of its specific objects the provision of anovel feeding and rotating means for the positive electrode whichobviates the necessity of providing means for feeding the electrode andother 15 means for rotating said electrode. This invention provides fora single means for accomplishing both functions.

A. further object of thisinvention is the provision of a novel feedcontrol meansior a the negative'electrode which is simple inconstruction and eificient in'operation to maintain the arc lengthconstant.

A further object of the invention consists in providing a negative headwhich obviates at the necessity of transmitting current through theentire negative electrode, which has heretofore necessitated suchexpedients as copper plating of the electrode in order to overcome thegreat resistance ofiered by the said negaao tive electrode. Bymyinvention T transmit the current only through the forward end of theelectrode adjacent the tip thereof.

A further object is the provision of means for mounting the negativeelectrode so as to 35 insure alignmentof the axis thereof at the tip inthe vertical plane through the positive electrode axis.

' A further object of my invention is the provision of novel means inthe negative head whereby the negative electrode may be retractedrapidly to its extreme ineffective limit" without the necessity ofoperating mechanism, such as screws, etc., which results only in veryslow movement of the electrode.

A further object of this invention is the provision of means foreliminating variations in the arc length due to variations in themechanism which nontrols the length of the are because of the radiationof the heat from v the are. My invention contemplates the provision offiat temperature means for the purpose of controlling the arc lengthwhich is not afiected, or afiected to only an inapprociable degree, byvariations in temperature.

Uther objects and advantages of this invention will be come apparent asthe description Tn the accompanying thereof proceeds. drawings Fig. 1 isa front view partly sectioned, and with parts omitted for the purpose ofclaritying the drawings, of the operating mechanism of a high intensityarc lamp having my invention applied thereto.

Fig. 2 is a detail view showing the gearin for rotating the positiveelectrode.

Fig. 3 is a wiring diagram.

Fig. l is a bottom view of the device shown in Fig. l.

Fig. 5 is a plan view of the negative carbon holder.

Fig. 6 is a view of the negative carbon holder.

Fig. 7 is a section taken on the line 7-7 of Fig. 6.

Fig. 8 is a section taken on the line 8-8 of Fig. 1.

Fig. 9 is a view similar to Fig. 6 showing a modified form of holder.

Referring to the drawings, l have shown a high intensityarc lightcomprising a base 10 supporting brackets 11 and12 upon whlch are mountedthe positive and negative heads respectively. The driving mechanism forfeeding and rotating the electrodes comprises a motor 15 operatingthrough gearing l6, l7, shaft 18, links 19, 20, said shaft and linksbeing connected by universal omts 21, 22 to drive an eccentric 25 (seeFig. 4) carrying acrank pin 26. Said crank pin engages a ll-shaped slot27 formed in a rec1procat-- ing member 28, comprising a shaft portion 29operating in fixed guides 30 and 31 to constrain the motion of saidmember 28 to lateral reciprocatory motion in a straight line.

Said reciprocating member 28 has plvoted thereto at 32 a pawl 33 adaptedto engage a ratchet 34 each time the reciprocatingmem-. ber 28 movestoward the right (in said Fig. 4) The rotation of ratchet 34 willcauserosaid shaft 35 having a gear 36 at its upper end meshing with a gear 37at one end of the sleeve which is supported in fixed hub 38. Said sleevehas fixed thereto at its other end beyond hub 38 a bracket 40,-uponwhich is fixed or supported the entire positive electrode rotating andfeeding mechanism so that as the ratchet 34 is rotated, bracket 40 willbe rotated to cause rotation and feeding of the positive electrode bythe mechanism now to be described.

Said bracket 40 has fixed thereto. a hub 41 through which extends ashaft carrying a gear 42 at its end, said gear 42 being adapted to rollaround a gear 43 fixed to the end of hub 38 between bracket 40 and saidhub. As bracket, 40 is rotated by the actuation of ratchet 34, planetarygear 42 is carried around the gear 43 and in so doing is rotated aboutits own axis. The shaft which carries gear 42, carries at its other enda worm 45 meshing with a gear 46 (see Fig. 8), said gear 46 beingmounted upon a shaft 47 carrying at its other end a pinion 48 meshingWith a gear 49, which is geared to a similar gear 50. Each of said gears49 and 50 is mounted on-the same shaft with rollers 51 and 52,respectively, in engagement with the positive electrode P. It is thusapparent that actuation of ratchet 34 in rotating bracket 40 rotatesalso the positive electrode and at the same time feeds said electrode,because the rollers 51 and 52 are not only driven in a direction to feedthe electrode but are at the same time rotated bodily together with thebracket 40, which supports them. This construction results in acontinuous and constant rotary and feeding movement of the positiveelectrode.

Pawl 33 is normally supported upon a guide or shelf of such dimensionsand so positioned that pawl 33 rides over the end of said guide'60 onlynear the end of the stroke of reciprocating member 28, so that said pawlengages, say, 1, 2, or 3 teeth. This number of teeth can be adjusted sothat the amount by which the positive carbon is constantly fed forwardis less than the normal rate of consumption of the positive electrode.With such a construction, it is apparent that the positive electrodewill continue to lose ground until it burns back sufficiently to causethe flame to engage the 'so-called third electrode 61 and establish acircuit through electromagnet 62, as will be apparent from the wiringdiagram of Fig. 3. When said magnet 62 is energized, it attracts itsarmature 63 to which is fixed the guide of shelf 60 so that the latteris drawn downwardly out of the path of pawl 33 and said pawl is now freeto engage the ratchet 34 throughout the entire stroke of reciprocatingmember 28 toward the right. The de ree of movement of ratchet 34 foreach stro e of member 28 is now much greater than the rate of constantfeed when pawl 33 is riding upon guide 60 and hence the positiveelectrode will be fed forward much more rapidly until the flame from thearc disengages electrode 61 thus breaking the circuit through magnet 62and permitting the shelf or guide 60 to be raised to its normal positionunder the action of spring 65. Thereafter, the positive electrode isagain fed forward at a constant rate less than the normal rate ofconsumption of said electrode. From the above description it will beapparent that I em loy a single mechanism for accomplishing t e twofunctions of rotating and feeding the positive electrode. It will beunderstood that the invention applies equally well to those lamps inwhich the positive electrode feed is controlled by the usual thermostatin place of the third electrode, said thermostat closing the samecircuit which is here closed by the engagement third, electrode.

The negativeelectrode N is adapted to be clamped in a clamp or holder70, mounted upon a carriage 71 through which extends loosely, withoutthreaded engagement theref with, a screw shaft 72. Engagement betweenthe screw shaft 72 and the electrode is effected by means of a finger 75extending from the clamp-70 (see Fig. 7) and en aging between adjacentthreads of the s aft 72 but not extending to the base thereof. R0-tation of the entire carriage and electrode is prevented by means of atongue 76 extending of the flame with the" downwardly from the carriage71 and en gaging in a slot within bracket 12.

The clamp 70 is pivotally mounted in carriage 71 about pivotal axis 77\so that by grasping a portion of said clamp, as for instance finger orextension 78 formed integral therewith, said clamp and electrode N maybe swung upwardly to disengage finger 75 from threaded shaft 72 andpermit the entire carriage, clamp and electrode to be moved rapidlydownwardly to its extreme lneffective limit, since as shown in Fig. 7,the threaded shaft 72 extends freely through the carriage 71. In thismanner, by inserting a suitable tool, such as pliers, and swinging theclamp upwardly, the negative electrode may be very rapidly retracted toits GXCIGIIIGIII- effective position.

The feeding of the negative electrode 15, of course, accomplished byrotatlng threaded shaft 72 in one direction or the other which causescorresponding feeding or retractive movement of the electrode. Rotationof shaft 72 in one direction or the other is accomplished by means suchas gear 80 fixed at one end to the shaft 72 meshing with gear 81 on theupper end of shaft 82 extending through base 10 and having a pair ofratchet wheels 8384 at its lower end. Said ratchet wheels have theirteeth oppositely disposed and said ratchet wheels are adapted to beengaged by pawls 8586, respectively, each 35 spring 94. In other 5 ber28 moves toward the left (in Fig. 1) said pawls would ordinarily engagetheir ratchets to operate the'negative electrode one in one directionandthe other in the other directlon. Obviously it is desired to haveonly that pawl in engagement with its respective ratchet as is necessaryto advance or retract'the negative electrode depending upon the lengthof arc. For this purpose there is provlded a guide member 90 interposedbetween pawls .85 and 86 and fixed to one end of a bell crank.

91 whose other arm 92 forms the armature of a voltage coil 93-. Normallysaid armature is retracted by a spring 94 so that guide 90 normallymaintains pawl 85 out of engagement with its respective ratchet butpermits pawl 86 to engage its ratchet and actuate it in a direction toconstantly feed the negative electrode forwardly. When, however, the

are becomes too short the voltage is increased and sufficient current isinduced in coil 93 to attract armature 92 against the action of spring94: and oscillate guide 90 to the other end of its movement to renderpawl 86 inefiective and permit pawl 85 to engage its re spective ratchetand thus retract the negative electrode. The length of are at which theretraction of the negative electrode begins may be varied by varying thetension of words the tension of spring 94 will determine the arc length.

While it has been stated above that the ten-' sion of spring 94:determines the length of arc, it has been found that variations in tem-40 perature of the surrounding medium during the operation of the-lighttend to vary the operation of coil 93 so that when a great amount ofheat is radiated from the arc, coil 93 will attract armature 92 soonerthan it otherwise would and thus maintain a different length of arc thanthe one determined upon. This would result in improper currentconditions in the arc and would impair its efficient operation. Toobviate this difficulty I have made coil 93 of a material having a verylow resistance so that said coil'is but slightly affected by temperaturevariations, and providing the necessary resistance b coupling in serieswith said coil 93, a resistance unit 95 having a-flat temperaturecoefiicient.

Said units are well known in the art and may consist of a nickle-chromealloy.q

By this means it will be apparent from Fig. 3 that the necessaryresistance is supplied but that the total resistance 9395 will beaffected by temperature changes only inthe ratio which resistance 93bears to resistance 95. This ratio can be made as small as desired andwill be limited by the fact that vari- ,ations of 1 to 3 volts in theare are permissible.

oftemperature changes.

It has hitherto been usual to pass the current through the negativebracket 12 and the entire length of electrode N before reaching the tip.By my invention I press the forward endflof negative electrode N intofirm gripping engagement with said bracket 10 at its forward supportingseat 100. This firm contact renders it easy for the current to travelthrough bracket 12to seat 100 and immediately to the forward end of theelectrode rather than through the l entire electrode, which offers avery high resistance. The firm engagement of the electrode N with itsseat 100 is efiected by the following mechanism.

- The rear end of the electrode is adapted to be gripped in seats 101,102 provided in two relatively movable members 103, 104. respectively,of the clamp or holder 70,said members being clamped firmly together bymeans such as a thumb screw 110. As hereinbefore stated the entire clampis pivotally mounted within carriage 71 for movement about pivotal axis7 7. The clamp is provided with extensions 112, each adapted to beengaged by one endof a spring 113 the other end of which is fixed to thepivotal shaft 77 in the carriage 71. This arrangement tends to swing theentire holder 70 clockwise'so as to press the forward end of saidelectrode downwardly into firfn engagement with seat 100. The projectionis made of such length that when the forward end of the negativeelectrode engages seat 100 it does not reach the bottom of the threadedchannel, thus'allowin full downward pressure to be applied to t eelectrode. I

The firm engagement of the negative electrode with its seat insuresalignment of the to a diameter slightly in excess of the electrodediameter to permit the electrode to slide freely therethrough when theholder 70 is raised about its pivot 77. Normally, however, the pressurebetween the front end of the electrode and seat 100 will cause the rearend of the electrode to be pressed against one side of the bore and heldfirmly in position, as shown in said Fig. 9.

In accordance with the provisions of the patent statutes I have hereindescribed the principle and operation of my invention, together yviththe apparatus which I now consider to represent the best embodimentthereof,but desire to have it understood that the apparatus shown isonly illustrative and that I the invention can be carried out by othermeans/Also, while it is designed to use the various features andelements in the combination and relations described, some of these maybe altered and others omitted without interfering with the more generalresults outlined, and the invention extends to such use.

Having described my invention, what I claim and desire to secure byLetters Patent is:

1. In a searchlight having apair of electrodes, means for rotating oneof said electrodes, means operated from said first-named means forfeeding said electrode, and means for driving said rotating means at aless rate than that necessary to feedthe electrode to compensate for thenormal rate of consumption thereof, and for feeding said electrode atfaster rate when the tip thereof has burned back a predetermined degree.

2. In a Searchlight having a pair of electrodes, an electrical conductoradjacent one of said electrodes, means for feeding said electrode, at aless rate than the normal rate of consumption thereof, and means forfeeding said electrode at'a faster rate when the flame of the arcengages said conductor.

3. In a searchlight having a pair of electrodes, an electrical conductoradjacent one of said electrodes, means for constantly feed ing saidelectrode comprising a pawl and ratchet mechanism, means forcontinuously actuating said pawl, means for normally limiting theengagement of said pawl with said ratchet to limit the rate of feed ofsaid electrode to less than the normal rate of consumption thereof, andmeans actuated by the engagement of the arc flame with said conductorfor rendering said last-named means ineffective and permit feeding ofsaid electrode at a faster rate.

4:. In a searchlight having a pair of electrodes, means for constantlyfeeding one of said electrodes, at a less rate than the normal rate ofconsumption thereof, said electrode feeding means comprisinga pawl andratchet mechanism, means for continuously actuating said pawl, means fornormally limiting the engagement of said pawl with said ratchet, andmeans rendered efiective in response to burning back of the tip ofsaid'electrode a predetermined degree for rendering said and means forvarying the rate of feed by varying the rate of rotation.

8. In an arc lamp, means for feeding and rotating an electrode at a ratedifferent from the normal rate of consumption, and automatic meansresponsive to the position of the are for altering the rate of rotationand feed to compensate for the difference between the rate ofconsumption and the normal feed to maintain the proper position of theelectrode.

9. In an arc lamp, means for feeding and rotating an electrodeat aslower rate than the normal rate of consumption and automatic meansresponsive to the osition of the are for increasing the rate of eedabove the normal rate of feed to maintain the proper position of theelectrode.

10. In a searchlight having a positive and a negative electrode, asource of power, variable speed mechanism driven thereby, a common meansfor feeding and rotating the posltive electrode driven fromsaid-mechanism, and separate means driven from said source of power forfeeding the negative electrode.

11. In a Searchlight having a positive and a negative electrode, asource of power, variable speed mechanism driven thereby, and a commonmeans for feeding and rotating the positive elect-rode driven fromsaid--mechanism.

'12. In a searchlight having a positive electrode, a common means forcontinuously rotating and feeding said electrode, means for varying therate of feed and rotation of said electrode and means responsive to theposition of the are for governing said rate of feed.

13. In a searchli ht having a pair of electrodes, means for. eeding thepositive electrode at a rate which is different from the normal rate ofconsumption thereof, and means responsive to the position of the arcingti thereof for temporarily altering the rate 0 feed to maintain the tipin the focus of the searchlight.

In testimony whereof I have afiixed my signature.

FRANK R. HOUSE.

last-named-means ineffective and permitting feeding of said elect-rodeat a faster rate.

5. In an electric arc lamp, an electrode,

means for normally imparting a periodic step-by-step feed to saidelectrode, and means for varying the amount of feed imparted to saidelectrode per period.

6. In an electric arc lamp, an electrode, a common means for normallyimparting a periodic step-by-step feed and rotationto said electrode,and means responsive to the position of the are for varying the amountof feed and rotation imparted to said electrode per period.

7. In an arc lamp, means for feeding and rotating an electrode at apredetermined rate,

